Abstract
The epoxide hydrolase activity towards styrene-7,8-oxide was investigated in the microsomal fraction of 18 human placentas from the midtrimester and the term of pregnancy. The enzymatic activity was 0.40 +/- 0.03 nmol/min/mg microsomal protein. No relation was found between gestational age and the rate of styrene oxide hydration. The kinetics of the enzyme were studied in 3 placentas. Biphasic kinetics were observed in each of the tissue specimens. The enzyme was inhibited both by 1,1,1-trichloropropene-2,3-oxide (0.25 mM) and benzo(a)pyrene-4,5-oxide (0.2 mM) which had similar inhibiting potency.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Benzopyrenes / pharmacology
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Dimethyl Sulfoxide / pharmacology
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Epoxide Hydrolases / antagonists & inhibitors
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Epoxide Hydrolases / metabolism*
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Epoxy Compounds / metabolism*
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Ethers, Cyclic / metabolism*
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Female
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Gestational Age
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Humans
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Kinetics
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Liver / embryology
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Liver / enzymology
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Liver / metabolism
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Methanol / pharmacology
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Microsomes / enzymology*
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Microsomes / metabolism
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Placenta / enzymology*
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Placenta / metabolism
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Pregnancy
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Rats
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Trichloroepoxypropane / pharmacology
Substances
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Benzopyrenes
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Epoxy Compounds
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Ethers, Cyclic
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Trichloroepoxypropane
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benzo(a)pyrene 4,5-epoxide
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styrene oxide
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Epoxide Hydrolases
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styrene oxide hydratase
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Methanol
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Dimethyl Sulfoxide